Multiple current reversals in forced inhomogeneous ratchets

Transport properties of overdamped Brownian particles in a rocked thermal ratchet with space dependent friction coefficient is studied. By tuning the parameters, the direction of current exhibit multiple reversals, both as a function of the thermal noise strength as well as the amplitude of rocking force. Current reversals also occur under deterministic conditions and exhibit intriguing structure. All these results arise due to mutual interplay between potential asymmetry, noise, driving frequency, and inhomogeneous friction.